Wobble pump



Feb. 10, 1970 A. R. BRAUN 3,494,293

WOBBLE PUMP Filed June 5, 1968 3 Sheets-Sheet 1 lr/bur 1?. Braun INVENTOR.

A. R. BRAUN WOBBLE PUMP Feb. 10, 1970 3 Sheets-Sheet 2 Filed June 5, 1968 Ar/fi 0r 1?. 5/00 INVENTOR BY W4 Mid ATTORNEY United States Patent Office 3,494,293 Patented Feb. 10, 1970 3,494,293 WOBBLE PUMP Arthur R. Braun, 209 E. Mildred, Cary, Ill. 60013 Filed June 3, 1968, Ser. No. 734,142

Int. Cl. F04c 3/00, 1/02 US. Cl. 103131 11 Claims ABSTRACT OF THE DISCLOSURE A rotary pump consisting of a cylinder block with an inner upstanding cylindrical wall, a piston with an upstanding cylindrical wall which fits within the upstanding wall and the outer wall of said cylinder, an inlet to the cavity of said upstanding wall and an outlet adjacent said outer wall and eccentric drive means for said piston. An interconnected array of such pumps which act as a pumping unit is also disclosed.

This invention relates to a pump and more particularly to a rotary pump of unique structure.

Many kinds of pumps, employing various principles and structures, are currently available. There is still, however, ample need for improvement, especially in view of the great diversity of applications for pumps.

The most eflicient structure for a pump, of course, is dependent upon the individual installation. Certain criteria do, however, apply to all pumps in general.

A pump must be economical. This requires that designs, fabrication methods, and materials be carefully selected with cost as well as durability being considered. It must also be economically manufactured with minimal parts and easily assembled, and thereafter durable for the longest possible time.

A pump must also be efficient. Friction must, therefore, be minimized, which requires that moving parts be held to as few as possible and forces exerted across moving surfaces be minimal.

It is also desirable that a pump provide a good flow rate. Such should be accomplished at a reasonable operating speed for a volume per cycle which is reasonably large, and preferably smooth.

A pump also should, itself, occupy as little volume as possible and be light so as to facilitate installation.

An object of this invention is to provide a pump that can be economically manufactured.

Another object is to provide a pump, of the above character, which has few parts, especially those which move during operation.

Still another object is to provide a pump, of the above character, which has little friction.

A further object is to provide a pump, of the above character, which can develop a large flow rate at moderate operating speeds.

A still further object is to provide a pump, of the above character, which effects a smooth flow.

Another object is to provide a pump, of the above character, which is self priming.

Another object is to provide a lightweight pump.

Another object is to provide a pump of the above character which occupies little volume in space.

Another object is to provide a pump of the above character which is durable.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

An unique pump has now been devised which satisfies these objectives. In essence, the pump comprises an eccentrically driven, rotary piston within a hollow cylinder block. The block has a substantially cylindrical upstanding inner wall concentric to the outer cylindrical wall of the block. The piston consists of an intermediate cylindrical wall which is eccentrically rotated with a wobble-like movement within said walls of said cylinder. Fluid from within the inner wall of the cylinder block, fed from an inlet, flows outwardly through a port in said wall and is directed around the outside of said wall by the action of said piston until it reaches an outlet on the block. The pump may also be operated in reverse fashion.

If desired, an array of pumps, each utilizing the basic structure just described may be used, the only change necessary being the relocation or repositioning of the inlet and outlet ports and the additional use of shaft connecting means.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the construction herer inafter set forth, and the scope of the invention will be indicated in the claims.

For a full understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is a perspective outer view of the pump of this invention.

FIG. 2 is an exploded perspective view of the several parts of the pump.

FIGS. 3, 4, 5 and 6 are sequential cross-sectional views of the pump of FIG. 1, along line 33, illustrating a pumping cycle.

FIG. 7 is a cross-sectional view along line 77 of FIG. 1.

FIG. 8 is a cross-sectional view, partially in perspective of an interconnected array of pumps of this invention.

Similar reference characters refer to similar parts throughout the several views of the drawings.

As best seen from FIG. 2, the pump of this invention comprises four basic components: a pump cover 10, a pump cylinder block 20, a pump piston 40, and a shaft 50.

The pump cover 10 comprises a disc 12 with a raised lip 14 about its perimeter with a groove 27 on its inside edge, and a shaft housing 16 extending from one side. The shaft housing 16 is stepped at its root end to form a short axle guide well 18 at the center of disc 12 (see FIG. 7).

Pump cylinder block 20 consists of an annular wall 22 with an outer pump cylinder block wall 24 centrally disposed therein extending outwardly therefrom. Wall 22 has a rim 26 which snap-fits into groove 27 of lip 14 of the cover 10, whereby these two parts can be easily assembled. The cover and the annular wall 22 of the cylinder block, when assembled, define an annular cavity around the hollow of said cylinder. This cavity receives the cylinder cavity cover disc of the piston as will be described hereinafter. Within and concentric to wall 24 is an inner cylindrical wall 30. An inlet port 28 feeds the cavity of said wall 30. An exhaust slot 32 is contained in said wall. Separator wall 34, adjacent to slot 32 extends to the outer cylinder block wall 24. Piston exhaust slot plugs 37 and 39 extend from opposite sides of separator wall 34 and are integral with inner chamber wall 30 and outer cylinder block wall 24, respectively. The function of these plugs will be seen as the description proceeds.

Adjacent to separator wall 34, within outer cylinder block wall 24, is an exhaust solt 36 which leads to an outlet port 38. As seen in FIG. 1, slot 46 may be formed by outlet port 38 slightly overlapping outer cylinder block wall 24.

Pump piston 40 consists of a cylinder cavity cover disc 42 with a ring shaped piston drive wall 44 centrally projecting therefrom. The disc 42 is of lesser diameter than piston cover disc 12 or cylindrical annular Wall 22. Interof the pump taken mediate the edge of disc 42 and piston drive wall 44 is tl'l annular piston wall 46. It is preferred that the volumes m the inside and the outside of wall 46 be substantially :qual to prevent forced leakage of incompressible fluids. iston wall 46 contains an inner piston exhaust slot 48 vhich straddles the separator Wall 34. Separator wall iston locater steps 49 adjacent disc 42 locate the piston :xhaust slot with respect to the separator wall 34. The .pace between the steps 49 is slightly greater than the hickness of separator wall 34. Piston exhaust slot plugs t7 and 39 sequentially enter the left and right portions )f inner piston exhaust slot 48 as the piston 40 wobbles, hereby providing increased blockage of the exhaust slot effect better separation of pumped liquid between :ycles, as will become evident as the description pro- :eeds.

Pump shaft 50 comprises a drive rod 54 terminated nternally by a coaxial rod guide disc 56. A piston drive :tud 58 projects from disc 56. It is offset from the axis )f disc 56 and shaft 54 and, in use, fits within piston lrive wall 44, of the piston 40. It should be evident from *"IG. 2 that as rod 54 is rotated by power means (not .hown), such as an electric motor, piston 40 therefore "otates eccentrically.

To assembly the pump, stud 58 is inserted into piston lrive wall 44 with disc 42 abutting against rod guide lisc 56. Then shaft 54 is placed within shaft housing 16 :0 that disc 56 fills well 18. Piston 40 is then placed into :ylinder block 20 in such manner that separator wall 54 fits within the space between steps 49 of the inner aiston exhaust slot 48. The rim 26 of cylinder block 20' s then snapped into grove 27 of enlarged rim 14 of Jump cover to completely finish the assembly of the Jump.

Referring to FIGS. 3 to 6, it may be seen that when he pump is operated, piston 40 wobbles within cylinder alock by eccentric piston drive stud 58 as shaft 54 is 'otated. Considering a counterclockwise rotation, as )iston 40 moves through its cycle, two lines of contact )ccur between wall 46 of the piston and walls and Z4 of the cylinder. These lines will progress in a counter- :lockwise fashion as the piston is wobbled. As this news, the volume exposed to inlet port 28 between wall 30 of the cylinder and wall 16 of the piston (the inner :hamber 70) increases. This draws fluid in through port 28 and subsequently through slot 32.

After piston 40 has made one 360 cycle, there is fluid :ompletely within the volume enclosed by wall 46. On the next 360 cycle of the inner chamber, the fluid is expelled into the outer volume between piston wall 46 and outer cylinder wall 24, but on the other side of separator wall 34. New fluid is also drawn into the volume enclosed by wall 46. To insure against backflow into inlet 28 or from outlet 38, one-way ball valves (not shown) may be utilized therein. Then, on the next cycle, the fluid is expelled from between walls 46 and 24 out through outlet 38, while the fluid within wall 44 is expelled through slot 32 to replace it.

During such motion of the piston, exhaust slot 48 is opened and closed, or closed and opened, on opposite sides of the separator wall 34. To improve its closing, piston exhaust slot plugs 37 and 39 have been incorporated into the cylinder structure, as seen in FIGS. 3 and 6. Plug 37 further closes exhaust slot 48, and in FIG. 4, plug 39 acts similarly. Spacer steps 49 center the piston with respect to the separator wall 34.

In essence, once started, the pump draws fluid in through inlet 28, forces it from the inside to the outside of wall 46 and then out the outlet 38. The direction of rotation is obviously of no moment. The pump of this invention may be used with clockwise or counterclockwise rotary motion of the piston. And no priming is necessary.

By comparing the structure just described with prior art structures, such as seen in: US. Patent 919,058; U5.

Patent 1,124,749; US. Patent 2,010,761; US. Patent 3,125,031; U.S. Reissue Patent 24,500; it becomes evident that a substantial improvement has been made. The entire cavity, except for the structural elements within the cylinder block, is used as the pumping volume. Even the interior of upstanding wall 30 is utilized. It should also be evident that in a single stage wobble pump, the line of contact must have considerable pressure in order to prevent leakage. With the two stage pump here described, the sealing action of the line of contact is assisted by the preceding and following flows of fluid, thereby greatly reducting the need for exact tolerance between moving parts.

It should further be evident from the above description that there is only sliding or rolling contact between the parts. Hence friction is kept to a minimum. Indeed, with the two cycle, lower pressure line of contact, there is always a thin layer or fluid between contacting surfaces to act as a lubricant.

It should also be evident that cover 10, cylinder 20, piston 40 and shaft 50 can all be easily and cheaply mass produce by plastic molding techniques. The plastic utilized may have filler, to further minimize friction or maximize strength or increase durability.

The parts of the pump are also easily assembled by a simple snap-fit. Indeed, such enables easy disassembly and repair or cleaning, should the need arise.

In use, the pump is of extremely small size for the volume fluid it is capable of pumping. And, because of its material of construction, it may be used to pump gases, liquids and even suspensions, whether corrosive or non-corrosive.

When assembled, the entire pump has only two moving parts which are essentially lubricated by the fluid being pumped. Therefore, maintenance is kept to a minimum.

It should be noted that the pump described may also be used as a hydraulic motor by simply injecting fluid through the inlet or the outlet and using the shaft as the driven member.

A plurality of pumps may, if desired, be used in array form. FIG. 8 illustrates a typical array. The same basic parts including pump cover 10, pump cylinder block 20, pump piston 40 and shaft 50 comprise each pump. However, the inlet port 28 and the outlet port 38 are angled and communicate with an inlet manifold and an outlet manifold 82. In addition the shaft of the pumps are interconnected by a piston drive stud extender 84 which extends from piston drive wall 44 to the wall of the 'block 20 of the lowermost (in FIG. 8) pump (pump 1 hereafter). Here it connects to a button crank 86. The crank 86 drives a crank follower 88 in the next adjacent (next (upper) in FIG. 8) pump (pump 2 hereafter), to which is afiixed a follower shaft 90. Shaft 90 acts in similar fashion to piston drive stud 58; that is, it fits within piston drive wall 44, but from the opposite side. It rotates eccentrically to drive piston 40 of said pump 2 in an eccentric manner. Hence pumps 1 and 2 operate in similar fashion. The same is true of the next upper pump (pump 3 hereafter). However, pumps 2 and 3 are interconnected by a drive crank 92 with a shorter extender 94 within piston drive wall 44 of pump 22. The crank follower 98 operatively connected thereto also has a short follower shaft 100. Thereafter the succeeding pumps utilize the structures .of pumps 1 and 2 in repeat form.

It should be evident that the array of pumps, just described, will act to feed outlet manifold 82. The flow will be more uniform, especially by locating the piston drive studs of each successive pump in degrees equidistantly around a 360 circumference.

I will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained, and, since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention, which, as a matter of language, might be said to fall therebetween.

Now that the invention has been described:

What is claimed is:

1. A rotary pump comprising a hollow cylinder block with a substantially cylindrical upstanding inner wall concentric to the outer wall of the block, a piston consisting of a cylindrical wall positioned intermediate said upstanding wall and said outer wall of said block, a separator wall between said upstanding and outer walls of said block, means to rotate said piston eccentrically, an inlet to the cavity of said upstanding wall and an outlet in the outer wall of said block, and an exhaust slot in said upstanding wall positioned on the 'far side to said outlet of said separator wall and an inner piston exhaust slot in said wall of said piston, said slot straddling said separator wall.

2. The pump of claim 1 wherein said cylinder block comprises a body with a pump cover detachably secured thereto, said pump cover snap-fitting to said body.

3. The pump of claim 2 wherein the pump cover contains a shaft housing, and the means to rotate said piston comprises a rotatable shaft within said housing, said shaft being driven by a power means external to said block, and an offset piston drive stud operatively connected to said piston.

4. The pump of claim 3 wherein said shaft housing has an annular step adjacent said cover, and said shaft has a guide disc to which said stud is affixed, said disc fitting within said annular step.

5. The pump of claim 2 wherein said body and said cover, when secured together, define an annular cavity around the hollow of said cylinder.

6. The pump of claim 5 wherein said wall of said piston is integral at one side with a cylinder cavity cover disc, said disc being located within said annular cavity of said cylinder block.

7. The pump of claim 1 wherein said piston has separator wall piston locator steps in its exhaust slot to locate said piston.

8. The pump of claim 7 wherein said piston has separator wall piston locator steps in its exhaust slot integral with said piston guide disc to locate said piston and the juncture of said upstanding and outer walls of said cylinder block with the separator wall having piston exhaust slot blockage steps which sequentially enter the piston exhaust slot as the piston is eccentrically driven.

9. The pump of claim 2 wherein said body contains said inlet and said outlet leads from the outer wall of said block.

10. The pump of claim 1 acting in conjunction with an array of similarly structured pumps with the means to rotate the piston of each pump being interconnected and the inlet and outlet of each pump communicating with a common inlet manifold and an outlet manifold respectively.

11. The pump of claim 10 wherein the means to ro tate each pump is spaced equidistantly in degrees about a 360 circle.

References Cited UNITED STATES PATENTS 141,226 7/1873 Jenkins et al. 9156 919,058 4/1909 Mortensen 103-131 940,817 11/1909 McLean et a1 230146 1,263,550 4/1918 Gollings 103131 1,780,109 10/1930 Berglund 103131 1,967,957 7/1934 Lucas 230-146 ROBERT M. WALKER, Primary Examiner WILBER J. GOODLIN, Assistant Examiner 

